Improvement in tubes for boilers akd kindred purposes



H. S. LANSDELL.

Tubes for Boilers and Kindred Purposes.

N0,149,138 Patented March 31,1874.

mar) STATES PATENT Orrrcn HENRY S. LANSDELL, OF BROOKLYN, NEW YORK.

IMPROVEMENT IN TUBES FOR BOILERS AR'D KINDRED PURPOSES.

Specification forming part of Letters Patent No. 149,138, dated Marsh 31, 1874; application filed January 1-2, 1874.

prove the character of tubes for boilers and kindred purposes, so that they will be the better able to resist the corrodin g action of the various soluble matters contained in the water ordinarily used for generating steam. To this endI coat the exterior of the tube with nickel, applying this nickel-plating by any of the processes adapted to secure the desired result. In

order to receive and retain this plating under the constantly-varying conditions of expansion and contraction to which the tube is subjected in use, the exterior surface of the tube must be prepared with unusual care, being made much smoother than in the ordinary processes of manufacture; and, with a view to secure a maximum of smoothness and a minimum of expansion and contraction, I prefer to make the tube of steel, drawn in a cold state through dies of the requisite form. Such a tube, the mere question of strength aside, will change its dimensions, under varying degrees of temperature, far less than ordinary iron or brass tubes, and, therefore, will be found the best adapted to the purpose sought.

An ordinary unplated boiler-tube is usually made cylindrical throughout, and of an external diameter about equal to the diameter of the holes in the boiler-head. Oonsequen tly, to insert it in its place in building or repairing the structure, it must be driven through the head by the application of considerable force, and with such friction against the edge of the hole through which it passes that the surface of the metal is almost necessarily cut and abraded. This would be fatal to the successful workings of the plate-tube so that it becomes necessary to devise some means of inserting such a tube in its place without injury to the plating. This might be done by making the tube cylindrical throughout, and of such diameter as to allow an easy play between it and the hole of the boiler-head, and then, after passing it through the hole, expand= ing it by means of a taper mandrel against the walls thereof, were it not that this mode of seating the tube, by expanding its ends, would tend to injure the pl ming upon this portion, the dimensions of which are thus permanently changed; and, in the case of a cold drawn steel tube, even the metal of the tube itself mightbe'cracked.

To obviate this difficulty I slightly enlarge the end of the tube before plating it, as shown in the accompanyingdrawing, in which Figure 1 is a longitudinal section of one end of one of my tubes, (shown as passing through the boil A tube thus constructed can be inserted in place without marring or injuring the plating that may have been placed upon its exterior. In order to produce more intimate contact between it and the walls of the hole in which it rests, the ordinary expander may be used to give a slight expansion to the metal after the tubeand the head have attained their ultimate relative position; but, on account of the previous tapering of the end of the tube, the expansion thus produced will be so very slight as not to weaken either the plating or the metal composing the tube.

What is hereby claimed as new is A tube for boilers and similar uses, enlarged at its extremity, andhaving its exterior plated throughout, substantially as and for the purposeset forth.

HENRY S. LANSDELL.

Witnesses:

SAMUEL A. DUNCAN, R0131. H.'DUN0AN. 

